I. Field of the Invention
The present invention relates to a transducer and a method of forming the same, and more particularly, to the improvement of a transducer for converting a signal, output from a semiconductor memory incorporated in a reading apparatus, to be sent to an electromagnetic head of the reading apparatus, and a method of forming the same.
II. Description of the related art including information disclosed under .sctn..sctn.1.97-1.99
Recently, IC (Integrated Circuit) cards have been developed which include a built-in large capacity semiconductor memory which performs a variety of data processing operations. Conventionally, reading out data stored in such a semiconductor memory requires that the electric terminals of an external unit serving as a data reader contact the terminals formed on the IC card. The more frequently the card is connected to, and disconnected from, the external unit, the greater the wear of the terminals of the unit and the IC card. When the terminals are worn to a certain extent, sparks will likely be generated as the IC card is connected to, or disconnected from, the external unit. Such sparks damage the IC card, rendering it less reliable than before. The following coupling method has been proposed as a means of overcoming this problem:
An electric signal generated inside an IC card is temporarily converted into a magnetic signal, which in turn is read by an electromagnetic converter incorporated in the external unit and having a read coil. This is known as a non-contact readout method. The IC card and the external electromagnetic converter each have a plurality of coils in addition to the read coil, such as a write coil, a read/write coil and a power clock coil.
The electromagnetic converter incorporated in the external unit can be replaced with an electromagnetic converter having no coils. If this is the case an electromagnetic converter having a coil is incorporated in the IC card, and a magnetic card reader is provided within the external unit. The card reader can be of the known type for reading data from the magnetic stripe formed on a card. The electromagnetic head of the card reader reads the output of the electromagnetic converter incorporated in the IC card.
The coil of the electronic converter incorporated in the IC card generates two magnetic fluxes near the center of a read head. These fluxes cancel out each other. Hence, when an electromagnetic head is located at the center of the read coil, the output from the winding on this head will be close to zero. On the other hand, when the head is positioned outside the outermost periphery of the coil, asymmetrical currents will flow through the core halves of the coil. In this case, the output of the head is not zero, but only a portion of the magnetic fluxes generated by the coil is effectively used. Consequently, the signal transfer efficiency is low.
The narrower the gap between the head and the converter, the higher the signal transfer efficiency. An anisotropic conductive film having a thickness of about 0.1 mm is interposed between the head and the converter and connected to the coil so as to supply power to the coil. The gap between the head and the converter cannot be less than 0.1 mm. Unless this gap is reduced, the signal transfer efficiency cannot be sufficiently high.